Description

Australian Crocodile Closeup

Although they appear to be similar to the untrained eye, crocodiles, alligators and the gharial belong to separate biological families. The gharial having a narrow snout is easier to distinguish, while morphological differences are more difficult to spot in crocodiles and alligators. The most obvious external differences are visible in the head with crocodiles having narrower and longer heads, with a more V-shaped than a U-shaped snout, compared to alligators and caimans. Another obvious trait is that the upper and lower jaws of the crocodiles are the same width, and the teeth in the lower jaw fall along the edge or outside the upper jaw when the mouth is closed; therefore, all teeth are visible unlike an alligator; which possesses small depressions in the upper jaw, into which the lower teeth fit. Also, when the crocodile’s mouth is closed, the large fourth tooth in the lower jaw fits into a constriction in the upper jaw. For hard-to-distinguish specimens, the protruding tooth is the most reliable feature to define the family that the species belongs to.[1] Crocodiles have more webbing on the toes of the hind feet and can better tolerate saltwater due to specialised salt glands for filtering out salt, which is present but non-functioning in alligators. Another trait that separates crocodiles from other crocodilians is their much higher levels of aggression.[2]